This invention relates to electromagnetic torquer assemblies and gyroscope apparatus including such torquer assemblies.
The invention is more particularly concerned with electromagnetic torquer assemblies for dynamically-tuned gyroscopes.
Torquer assemblies are used in gyroscope apparatus to provide a restoring torque on the gyroscope inertia ring, the restoring torque necessary to maintain the ring in a datum position being a measure of the rate of displacement of the gyroscope.
Torquers comprise one or more electrical coils and one or more permanent magnets mounted on the inertia ring. The coils are supplied with electric current to produce a magnetic field that interacts with the field of the permanent magnets, thereby providing a restoring torque on the ring. Conventionally, each coil is of rectangular shape and is mounted at one edge only, the other edge projecting within a gap in the magnet assembly. This arrangement, however, has several disadvantages in that, because the coil is supported at one edge, it lacks rigidity and has poor thermal contact with the casing. The magnet assembly is typically a single magnet having two soft iron pole pieces defining the gap within which the coil projects. The efficiency of such an arrangement is low because of leakage of flux from the magnet assembly, and because only a part of the coil is located within the strongest part of the field produced by the permanent magnet.